Centrifugal compressor

Abstract

The centrifugal compressor provided by the application comprises an impeller, a diffuser and a backflow device. The diffuser comprises a cover plate and a partition plate. The cover plate is installed on the backflow device and forms a containing cavity with the backflow device. The partition plate is accommodated in the containing cavity and divides the containing cavity into a supply air passage communicated with an air inlet. The supply air passage comprises a diffuser passage, a reversing passage and a backflow passage. The reversing passage has opposite first and second side walls. The first side wall is arranged on the inner side wall of the cover plate, and the second side wall is arranged on the outer side wall of the partition plate. The first side wall comprises a first arc surface, a second arc surface and a first plane arranged between the first arc surface and the second arc surface. The second side wall comprises a third arc surface and a fourth arc surface. According to the scheme, the gas in the diffuser passage is smoothly transitioned into the backflow passage, and the loss of gas flow from the diffuser passage into the backflow passage is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of centrifugal compressor, in particular to a centrifugal compressor. BACKGROUND

[0002] The centrifugal compressor is also called radial flow centrifugal compressor, which is mainly used to transport air, various process gases or mixed gases and increase the pressure thereof. The multi-stage centrifugal compressor generally comprises a main shaft, a first-stage impeller, a first-stage cover plate, a first-stage diffuser, a return flow device, a second-stage impeller, a second-stage cover plate, a second-stage diffuser and the like. When the centrifugal compressor is working, the main shaft drives the first-stage impeller to rotate, and the gas from the inlet chamber is thrown by the first-stage impeller into the first-stage diffuser passage formed by the first-stage cover plate and the first-stage diffuser. After the gas passes through the first-stage diffuser passage, it enters the inlet flow passage in front of the second-stage impeller through the return flow device. The second-stage impeller is also driven by the main shaft to rotate, and the gas from the inlet flow passage is thrown by the second-stage impeller into the second-stage diffuser passage formed by the second-stage cover plate and the second-stage diffuser. In this process, the gas is gradually compressed, thereby having a very high pressure. In the centrifugal compressor, the return flow device is used for guiding the flow, and guiding the strong swirling gas flow flowing out of the first-stage diffuser passage to enter the next-stage impeller uniformly in the circumferential direction or a specific direction.

[0003] The gas experiences 180° turning in the diffuser passage and enters the return flow passage, and finally enters the next-stage impeller. At present, the flow conditions in the curved passage and the return flow device are relatively poor, which causes relatively large flow loss of the gas. SUMMARY

[0004] The centrifugal compressor provided by the present application is used to solve the technical problem that the flow conditions in the curved passage and the return flow device are relatively poor, which causes relatively large flow loss of the gas in the prior art.

[0005] In order to solve the above technical problems, the present application adopts the following technical solutions:

[0006] A centrifugal compressor comprises an impeller, a diffuser and a return channel, the impeller is installed at an air inlet of the diffuser; the diffuser comprises a cover plate and a partition plate, the cover plate is installed at the return channel and forms a containing cavity with the return channel, the partition plate is contained in the containing cavity and separates the containing cavity into an air supply channel communicated with the air inlet; the air supply channel comprises a diffuser channel, a reversing channel and a return channel, the diffuser channel is communicated with the air inlet, the reversing channel is arranged between the diffuser channel and the return channel; the reversing channel has opposite first and second side walls, the first side wall is arranged at an inner side wall of the cover plate, the second side wall is arranged at an outer side wall of the partition plate, the first side wall comprises a first arc surface, a second arc surface and a first plane, the first plane is arranged between the first arc surface and the second arc surface, the second side wall comprises a third arc surface and a fourth arc surface.

[0007] In one of the embodiments, a guide channel is arranged between the diffuser channel and an outlet of the impeller, the guide channel has opposite third and fourth side walls, the third side wall is arranged at the cover plate, the fourth side wall is arranged at the partition plate, the third side wall is outwardly flared from the diffuser channel to the impeller.

[0008] In one of the embodiments, an included angle between the third side wall and a vertical direction ranges from 1° to 15°.

[0009] In one of the embodiments, a width of the diffuser channel is 0.75-1.0 times a width of an end of the guide channel towards the impeller.

[0010] In one of the embodiments, the return channel has opposite fifth and sixth side walls, the fifth side wall is arranged at the partition plate, the sixth side wall is arranged at the return channel, the fifth side wall is gradually outwardly flared from an inlet of the return channel to an outlet of the return channel, and an included angle between the fifth side wall and a vertical direction ranges from 1° to 10°.

[0011] In one of the embodiments, the return channel is provided with an air outlet, a flow-out channel is arranged between the air outlet and the return channel, the flow-out channel has opposite seventh and eighth side walls, the seventh side wall is arranged at the partition plate, the eighth side wall is arranged at the return channel, the seventh side wall comprises a fifth arc surface, and the eighth side wall comprises a sixth arc surface.

[0012] In one of the embodiments, the fifth arc surface is tangent to the fifth side wall, and the sixth arc surface is tangent to the sixth side wall.

[0013] In one of the embodiments, the impeller comprises a cover, blades and a disc, the blades are arranged between the cover and the disc, the cover plate is provided with a first step surface matched with the cover, and the partition plate is provided with a second step surface matched with the disc.

[0014] In one of the embodiments, the return flow device is provided with return flow blades on the side facing the partition plate, and the return flow blades abut against the partition plate.

[0015] In one of the embodiments, the centrifugal compressor further comprises a cover seal arranged at the outer edge of the air inlet and matched with the impeller for sealing the cover plate.

[0016] Compared with the prior art, the centrifugal compressor provided by the application has the following advantages:

[0017] The first side wall and the second side wall form a 180° bend to change the movement direction of the airflow from the diffuser passage; the first arc surface and the third arc surface correspond to each other, and the difference between the radii of the two is the same as the width of the diffuser passage. The first flat surface can control the length of the reversing passage, and accordingly, the length of the second flat surface and the first side wall between the third arc surface and the fourth arc surface can be matched to smoothly transition the gas in the diffuser passage to the return flow passage, avoiding the loss of gas flow from the diffuser passage to the return flow passage. BRIEF DESCRIPTION OF DRAWINGS

[0018] The following drawings are only used to better understand the technical solutions of the application, and are not a limitation of the application, and those skilled in the art can obtain other drawings according to the technical solutions of the application.

[0019] Figure 1 The structure diagram of the centrifugal compressor provided by the application Figure 1 ;

[0020] Figure 2 The explosion diagram of the centrifugal compressor Figure 1 ;

[0021] Figure 3 The sectional view of the centrifugal compressor Figure 1 ;

[0022] Figure 4 The structure diagram of the cover plate Figure 3 ;

[0023] Figure 5 The structure diagram of the partition plate and the return flow device Figure 3 ;

[0024] Figure 6 The structure diagram of the partition plate and the return flow device Figure 3Schematic diagram of the structure of the middle impeller.

[0025] Description of labels:

[0026] 100, centrifugal compressor; 101, air supply channel; 10, impeller; 11, wheel cover; 12, blades; 13, wheel disc; 20, diffuser; 21, cover plate; 211, first step surface; 212, seventh curved surface; 22, partition; 221, second step surface; 222, eighth curved surface; 23, air inlet; 30, return flow device; 31, return flow blade; 32, air outlet; 40, diffuser channel; 50, reversing channel; 51, first side wall; 5 11. First curved surface; 512. Second curved surface; 513. First plane; 52. Second side wall; 521. Third curved surface; 522. Fourth curved surface; 60. Return channel; 61. Fifth side wall; 62. Sixth side wall; 70. Guide channel; 71. Third side wall; 72. Fourth side wall; 80. Outflow channel; 81. Seventh side wall; 811. Fifth curved surface; 82. Eighth side wall; 821. Sixth curved surface; 90. Wheel cover seal. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] In order to better describe and illustrate the embodiments of the present application, reference may be made to one or more drawings, but the additional details or examples used to describe the drawings should not be considered as limiting the scope of the invention of the present application, any of the currently described embodiments or preferred methods.

[0029] It should be noted that when a component is referred to as being "connected" to another component, it may be directly connected to the other component or there may be an intermediate component. When a component is referred to as being "disposed on" another component, it may be directly disposed on the other component or there may be an intermediate component.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

[0031] In addition, unless otherwise defined, the orientation words such as "upper", "lower", "left", "right" used in the present application are described with respect to the orientation shown in the drawings.

[0032] As shown in Figures 1 to 3 , the present application provides a centrifugal compressor 100 for conveying air or mixed gas and increasing the pressure of the air or mixed gas.

[0033] Specifically, the centrifugal compressor 100 comprises an impeller 10, a diffuser 20 and a return flow device 30, the impeller 10 is installed at an air inlet 23 of the diffuser 20, the diffuser 20 comprises a cover plate 21 and a partition plate 22, a containing cavity (not shown in the figure) for accommodating the partition plate 22 is formed between the cover plate 21 and the return flow device 30, the partition plate 22 is accommodated in the containing cavity and separates the containing cavity into a supply air passage 101 which communicates with the air inlet 23; the supply air passage 101 comprises a diffuser passage 40, a reversing passage 50 and a return flow passage 60, the diffuser passage 40 communicates with the air inlet 23, the reversing passage 50 is arranged between the diffuser passage 40 and the return flow passage 60.

[0034] It can be understood that the diffuser passage 40 is formed between the cover plate 21 and the partition plate 22, the return flow passage 60 is formed between the partition plate 22 and the return flow device 30, the reversing passage 50 is arranged between the return flow passage 60 and the diffuser passage 40, the return flow passage 60 communicates with the diffuser passage 40 through the reversing passage 50 and is used for guiding the gas from the diffuser passage 40.

[0035] Wherein, the return flow device 30 is fixed on the diffuser 20 by a fastener (not shown in the figure), the return flow device 30 is provided with a through hole, the cover plate 21 is provided with a fastening hole, the fastener is fixedly connected with the through hole and the fastening hole to fix the return flow device 30 on the cover plate 21. Specifically, the fastener is a fastening bolt, the outer side wall of the fastening bolt is provided with an external thread, and the inner side wall of the fastening hole is provided with an internal thread matched with the external thread.

[0036] Further, as shown in Figure 3 , Figure 4 and Figure 5 , the reversing passage 50 has opposite first and second side walls 51 and 52, the first side wall 51 is arranged on the inner side wall of the cover plate 21, the second side wall 52 is arranged on the outer side wall of the partition plate 22, the first side wall 51 comprises a first arc surface 511, a second arc surface 512 and a first flat surface 513, the first flat surface 513 is arranged between the first arc surface 511 and the second arc surface 512, and the second side wall 52 comprises a third arc surface 521 and a fourth arc surface 522.

[0037] It can be understood that the first side wall 51 and the second side wall 52 constitute a 180° bend, changing the movement direction of the gas flow from the diffuser passage 40; the first arc surface 511 corresponds to the third arc surface 521, and the difference between the radii of the two is the same as the width of the diffuser passage 40. The first plane 513 can control the length of the reversing passage 50, and correspondingly, the third arc surface 521 and the fourth arc surface 522 can increase the length of the second plane (not shown) to match the first side wall 51, so as to smoothly transition the gas in the diffuser passage 40 to the return passage 60, avoiding the loss of gas flow from the diffuser passage 40 to the return passage 60.

[0038] Further, as shown in Figure 3 , Figure 4 and Figure 5 , the diffuser passage 40 and the outlet of the impeller 10 are provided with a flow guide passage 70, the flow guide passage 70 has opposite third and fourth side walls 71 and 72, the third side wall 71 is provided on the cover plate 21, the fourth side wall 72 is provided on the partition plate 22, and the third side wall 71 is outwardly flared from the diffuser passage 40 to the impeller 10.

[0039] It can be understood that the third side wall 71 is outwardly flared from the diffuser passage 40 to the impeller 10, which can prevent backflow of gas in the diffuser passage 40 and improve the flow state of the gas therein, which is beneficial to improve the performance of the centrifugal compressor 100.

[0040] In this embodiment, the included angle between the third side wall 71 and the vertical direction is 1°-15°, which can prevent backflow of gas in the diffuser passage 40.

[0041] Further, the width of the diffuser passage 40 is 0.75-1.0 times the width of the flow guide passage 70 towards the one end of the impeller 10.

[0042] It can be understood that by changing the width of the diffuser passage 40 and the width of the flow guide passage 70 towards the one end of the impeller 10, the flow of gas in the diffuser passage 40 can be controlled to ensure the uniformity of the gas flow from the outlet of the impeller 10 in the diffuser passage 40.

[0043] Further, as shown in Figure 5 , the return passage 60 has opposite fifth and sixth side walls 61 and 62, the fifth side wall 61 is provided on the partition plate 22, and the sixth side wall 62 is provided on the return flow device 30, the fifth side wall 61 gradually flares outward along the direction from the inlet of the return passage 60 to the outlet of the return passage 60.

[0044] It can be understood that since the gas entering into the backflow channel 60 from the pressure expansion channel 40 is an unstable flow with a large flow rate, the flow loss is large, and the width of the inlet of the backflow channel 60 is designed to be ≤ the width of the outlet of the backflow channel 60, so that the backflow channel 60 can play a certain pressure expansion role, reduce the flow rate, and improve the stability of the gas flow; considering that the roughness of the inner surface of the backflow channel 60 is large, the width of the outlet of the backflow channel 60 is further designed to be not more than four times the width of the inlet of the backflow channel 60, so as to ensure that the gas can smoothly flow through the backflow channel 60; the sixth side wall 62 is vertical, and the included angle between the fifth side wall 61 and the vertical direction can ensure that the gas flow in the backflow channel 60 is uniform and has a certain gas acceleration or gas deceleration pressure expansion effect.

[0045] In the embodiment, the included angle between the fifth side wall 61 and the vertical direction ranges from 1° to 10°, which can guide the gas to flow towards the fifth side wall 61 and improve the flow guiding effect.

[0046] Wherein, the cover plate 21 can ensure smooth transition between the second arc surface 512 and the sixth side wall 62 when it is installed on the backflow device 30; in order to avoid interference that may occur during assembly of parts, a gap of 0.5 mm-1 mm is provided between the cover plate 21 and the backflow device 30.

[0047] Further, as shown in the drawings, Figure 5 the backflow device 30 is provided with an air outlet 32, a flow-out channel 80 is provided between the air outlet 32 and the backflow channel 60, the flow-out channel 80 has opposite seventh and eighth side walls 81 and 82, the seventh side wall 81 is provided on the partition plate 22, the eighth side wall 82 is provided on the backflow device 30, the seventh side wall 81 comprises a fifth arc surface 811, and the eighth side wall 82 comprises a sixth arc surface 821.

[0048] It can be understood that the flow-out channel 80 can change the movement direction of the gas flow in the backflow channel 60, and the fifth and sixth arc surfaces 811 and 821 constitute the flow-out channel 80, so that the gas flow can smoothly transition to the air outlet 32, which is beneficial to improve the performance of the centrifugal compressor 100.

[0049] Preferably, the fifth arc surface 811 is tangent to the fifth side wall 61, and the sixth arc surface 821 is tangent to the sixth side wall 62. Further, the gas flow can smoothly transition to the air outlet 32.

[0050] Further, as shown in the drawings, Figure 6 the impeller 10 comprises a cover 11, blades 12, and a disc 13, the blades 12 are arranged between the cover 11 and the disc 13, the cover plate 21 is provided with a first stepped surface 211 matched with the cover 11, and the partition plate 22 is provided with a second stepped surface 221 matched with the disc 13.

[0051] It can be understood that the outer circle of the wheel cover 11, the outer circle of the blade 12 and the outer circle of the wheel disc 13 can be flexibly adjusted. After the outer circle of the wheel cover 11 and the outer circle of the wheel disc 13 are matched with the diffuser passage 40, the variable working condition operation of the centrifugal compressor 100 can be realized by changing the outer circle of the blade 12 and the running speed of the impeller 10, thereby improving the flexibility of the stage design of the centrifugal compressor 100.

[0052] The distance between the first step surface 211 and the wheel cover 11 is 1-3 mm. The first step surface 211 and the third side wall 71 are connected through a seventh arc surface 212. The seventh arc surface 212 can have a radius of 0.5-3 mm, which is used for the transition between the first step surface 211 and the third side wall 71.

[0053] The distance between the second step surface 221 and the wheel disc 13 is 1-3 mm. The second step surface 221 and the fourth side wall 72 are connected through an eighth arc surface 222. The eighth arc surface 222 can have a radius of 0.5-3 mm, which is used for the transition between the second step surface 221 and the fourth side wall 72.

[0054] Further, as shown in Figure 2 The return flow blade 31 is arranged on one side of the return flow device 30 facing the partition plate 22, and the return flow blade 31 abuts against the partition plate 22.

[0055] It can be understood that the return flow blade 31 is fixed on the return flow device 30 and is arranged towards the return flow passage 60, so that the return flow blade 31 is arranged in the return flow passage 60, so that when the gas enters the return flow passage 60, the gas is uniformly guided by the return flow blade 31. In particular, the position where the return flow blade 31 inlet starts is located at the position where the fourth arc surface 522 and the fifth side wall 61 meet, and the position where the return flow blade 31 outlet ends is located at the position where the sixth side wall 62 and the sixth arc surface 821 meet.

[0056] In the present embodiment, the return flow blade 31 is integrally arranged with the return flow device 30, and the return flow blade 31 and the like can be directly machined on the return flow device 30, thereby simplifying the machining process of the return flow device 30. Of course, in other embodiments, the return flow blade 31 can also be welded on the return flow device 30, as long as the return flow blade 31 can be fixed on the return flow device 30.

[0057] Further, as shown in Figure 2 The centrifugal compressor 100 further comprises a wheel cover sealing member 90, which is arranged at the outer edge of the air inlet 23 and cooperates with the impeller 10 to seal the cover plate 21.

[0058] It can be understood that the wheel cover seal 90 is annular, the wheel cover seal 90 is fixedly connected with the cover plate 21, the inner edge of the wheel cover seal 90 is in clearance fit with the wheel cover 11 of the impeller 10, and the wheel cover 11 can rotate relative to the wheel cover seal 90. The wheel cover seal 90 prevents the gas flow at the outlet of the impeller 10 from flowing back to the inlet of the impeller 10.

[0059] The wheel cover seal 90 is made of a low-hardness material. The wheel cover seal 90 is fixed on the cover plate 21 by bolts (not shown in the figure), a through hole (not shown in the figure) is formed on the wheel cover 11, a fixing hole (not shown in the figure) corresponding to the through hole is formed on the cover plate 21, the bolts are provided with external threads, the inner side wall of the fixing hole is provided with internal threads matched with the external threads, and the bolts are threadedly connected with the fixing hole through the through hole.

[0060] The technical features of the above-described embodiments can be combined arbitrarily, and to make the description concise, all possible combinations of the technical features in the above-described embodiments are not described, however, as long as the combinations of the technical features do not exist, it should be considered that they are within the scope of the present disclosure.

[0061] The above-described embodiments only express several implementation manners of the present application, the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the patent right of the present application. It should be pointed out that for ordinary skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent right of the present application should be subject to the appended claims.

Claims

1. A centrifugal compressor comprising an impeller, a diffuser, and a return flow device, wherein the impeller is mounted at an air inlet of the diffuser; The diffuser includes a cover plate and a partition plate, wherein the cover plate is mounted on the returner and forms a receiving cavity between the cover plate and the returner, and the partition plate is received in the receiving cavity and divides the receiving cavity into an air supply channel connected to the air inlet; The air supply channel includes a pressure diffusion channel, a reversing channel and a return channel, the pressure diffusion channel is connected to the air inlet, and the reversing channel is provided between the pressure diffusion channel and the return channel; it is characterized in that, The reversing channel has a first side wall and a second side wall opposite to each other, the first side wall is arranged on the inner side wall of the cover plate, the second side wall is arranged on the outer side wall of the partition plate, the first side wall includes a first curved surface, a second curved surface and a first plane, the first plane is arranged between the first curved surface and the second curved surface, and the second side wall includes a third curved surface and a fourth curved surface; The return channel has a fifth sidewall and a sixth sidewall opposite to each other, the fifth sidewall being provided on the partition, the sixth sidewall being provided on the return flow device, the fifth sidewall gradually flaring outward along a direction from the inlet of the return channel to the outlet of the return channel, and an angle with the vertical direction being in a range of 1°-10°; the return flow device is provided with an air outlet, an outflow channel being provided between the air outlet and the return channel, the outflow channel having a seventh sidewall and an eighth sidewall opposite to each other, the seventh sidewall being provided on the partition, the eighth sidewall being provided on the return flow device, the seventh sidewall including a fifth curved surface, and the eighth sidewall including a sixth curved surface; The return blade is provided on the side of the returner facing the partition, and the return blade is in contact with the partition, and the starting position of the return blade inlet is located at the intersection of the fourth curved surface and the fifth side wall, and the ending position of the return blade outlet is located at the intersection of the sixth side wall and the sixth curved surface.

2. The centrifugal compressor according to claim 1, characterized in that A guide channel is provided between the diffuser channel and the outlet of the impeller, and the guide channel has a third side wall and a fourth side wall relative to each other. The third side wall is provided on the cover plate, and the fourth side wall is provided on the partition plate. The third side wall extends outward from the diffuser channel to the impeller.

3. The centrifugal compressor according to claim 2, characterized in that The included angle between the third side wall and the vertical direction is in the range of 1°-15°.

4. The centrifugal compressor according to claim 2 or 3, characterized in that: The width of the pressure diffusion channel is 0.75 to 1.0 times the width of the guide channel toward one end of the impeller.

5. The centrifugal compressor according to claim 1, characterized in that The fifth arcuate surface is tangent to the fifth side wall, and the sixth arcuate surface is tangent to the sixth side wall.

6. The centrifugal compressor according to claim 1, characterized in that The impeller includes a wheel cover, blades and a wheel disc, the blades are arranged between the wheel cover and the wheel disc, the cover plate is provided with a first step surface that cooperates with the wheel cover, and the partition is provided with a second step surface that cooperates with the wheel disc.

7. The centrifugal compressor according to claim 1, characterized in that The centrifugal compressor further includes a wheel cover seal, which is placed on the outer edge of the air inlet and cooperates with the impeller to seal the cover plate.

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